SBIR-STTR Award

Vacuum Insulating Glass (VIG) is like a flat thermos bottle for windows. V-Glass has developed a VIG design, with tiny wire whiskers as pane spacers, that can insulate up to 3X better than triple pane. However, glass is subject to “delayed failure”, and the contact stress between whisker and glass is extremely high. Such damage, whether cosmetic or life-shortening, raises a warranty cost risk that will be a barrier to investors. In this Phase I project, V-Glass will collaborate with the University of Sydney (USyd) to determine if a workable combination of spacer diameter, length and grid pitch can be identified which will allow achieving an R10 window with a life of at least 20 years. Using its prior work evaluating the cylindrical pillars used by most vacuum glass competitors, USyd will extend its expertise to include rolling whisker spacers, a friction-free and low-heat-loss alternative. The testing will be validated by cold weather field testing of an optimized VIG. This work is expected to verify that the V-Glass vacuum glass design can enable an affordable, long-life window having a rating of at least R-10, a goal of the DOE Window Roadmap. Successful development of this new protocol will facilitate commercialization of new Advanced Insulating Glass concepts. Affordable AIG options will reduce national energy use, with commensurate greenhouse gas reduction. No longer will lack of accurate, low-cost, and objective third-party verification of center-of-glass U-value be a barrier to investment. A new well-accepted standard will facilitate keeping U.S. firms at the forefront of AIG development, a large and important global market.

The one remaining barrier to achieving a marketable R-10 window is the high manufacturing cost of solderglass-sealed vacuum glass. To remedy this, edge seal material must be changed from meltable solderglass to cold-weldable aluminum foil, speeding up the manufacturing rate by over 700X. Phase I research showed that rod-shaped pane spacers, or whiskers, are the best shape available. They can enable R-10 capable vacuum glass (a DOE windows roadmap goal). Moreover, when annealed glass is used (75% of market), only whiskers enable R-10, while conventional pillars are inherently constrained to R-6. Now that R-10 can be achieved without using a third pane of glass, the focus can move to the seals. The manufacturing cost for first generation vacuum glass is over twice that of dual pane insulating glass. The problem is inherent in the use of solderglass seals, which require a heating-cooling cycle of six hours. In contrast, one dual pane unit can be sealed every 30 seconds. To compete with dual pane, next-generation vacuum glass seal material must migrate from solderglass to aluminum foil, cold-welded directly to glass in only a fraction of a second. To complement this, thermal degassing can be replaced with room-temperature ion peening, and the use of a getter that can finish the evacuation process after seal-off and preserve life for 50 years. In this Phase II project, V-Glass will collaborate with the Edison Welding Institute to migrate the proven V-Glass cold-welding process from an ultrasonic seam welder to an ultrasonic bar welder that is over 100X faster for a single head. To migrate away from thermal degassing, V- Glass will collaborate with the University of Sydney to identify and minimize sources of residual gas that cause vacuum decay. Any remaining residual gas will be scavenged post-sealoff by getters or ion peening. A successful outcome will allow each foil-sealed window to be fabricated in 30 seconds, and maintain vacuum for at least 50 years. The R-10 product will be validated by testing. Commercial Applications and Other

Benefits:
A successful project will provide private investors the confidence they require to build the first commercial R10-capable VIG line as soon as2020, beating time target of the DOE windows roadmap. Widespread use of R-10 windows can reduce total US energy use (and greenhouse gas emissions) as much as 3%, and help position the U.S. at the forefront in a global market totaling $25 billion per year.